As the demographics Of the United States populace continues to skew towards older age groups, determining the processes that underlie the physical deterioration that occurs in normal aging becomes increasingly relevant. At this time a genetic approach to the analysis of changes that occur with aging is possible and promises to yield new insight into these processes. Recently genes that have been implicated as the causes of disorders of human premature aging have been identified and cloned. Werner's syndrome is one such disorder. The overall aim of this proposal is to use the molecular analysis of the Werner's syndrome protein to better understand the aging process in the normal human population. This analysis will proceed along three interrelated lines of investigation. First, the hypothesis that the specificity of the Werner's protein function is determined by protein-protein interaction will be tested using the method of yeast two-hybrid cloning. Second, the Werner's gene will be expressed in E. coli and polyclonal antiserum produced for an immunocytochemical analysis. Third, novel -Werner's syndrome gene mutations will be identified in spontaneously occurring human sarcomas by analysis for loss of heterozygosity at the Werner's locus. For those tumors showing LOH at the Werner's locus, the presence of mutations in the remaining Werner's sequences will be determined. The candidate is an M.D. and Ph.D., whose medical training was at Harvard Medical School and Ph.D. thesis work was performed with Phillip Sharp at the Massachusetts Institute of Technology. At the time of this award, he will have completed training in internal medicine and subspecialty training in hematology and medical oncology. Although he has had much experience in biochemistry and molecular biology, he has dedicated himself exclusively to rigorous clinical training for the last five years. The work proposed in this application is a considerable departure from his prior experiences, and entering the field of research on the molecular genetics of aging is a substantial career change. The balanced program of mentored research, didactic and career development activities proposed in this application will provide the foundation for a successful career as an independent investigator in the field of the biology of aging.